Thread cutting device



Dec. 16,1941.

R. B. PEALER THREAD CUTTINGDEVICE Filed June 28, 1940 I ULlIlIl Patented Dec. 16, 1941 THREAD CUTTING DEVICE Robert B. Pealer, Parkman, Qhio,.a s signor to poration of Ohio Application June 28 1940, Serial a head and shifted in and out radially to set'the chaser for different sizes of pipe, by turninga cam having a scroll connection with the chasers.

Such cam after being set for the proper size of pipe is operated by a lever and crank mechanism to position the chasers simultaneously for threading or to withdraw them to free the pipe after the threading. is completed.

The present application. is in the nature of a simplification of the construction shown in the patent mentioned and is designed to make the action more certain, to reducethe chance of the chasers getting out of adjustment, and to enable the device to be more cheaply constructed.

Briefly, my invention provides an operating mechanism for the set of chasers, which is normally non-adjustable, but movable merely to in and out position. At the same time, provision is made whereby, at a little trouble, the user may make an adjustmentfor cutting a thread which is slightly off the standard, by setting the'chas ers of the unit slightly closer together or slightly Beaver Rip Tools, Inc, War en, Ohi a orfarther apart than normal. This adjustment is not sufficient to enable the threading of different standard sizes of pipe, but merely provides for those occasional instances where it is necessary to cut a thread which does not conform to the standard.

My invention is illustrated in the drawing hereof and is hereinafter more fully explained,

and the essential and novel features are summarized in the claims.

In the drawing, Fig. 1 is a side elevation. of a power machine embodying my invention; Fig. '2 is a vertical transverse section. on a larger scale, looking at the face of the threading'head, as indicated by the line 2-2 on Fig. 1; vFig. 3 is a substantially vertical section through the cutting head in offset plane indicated by the line :33 on Fig. 2.

As shown in Fig. 1, It indicates a suitable bed having a standard H in which is mounted the barrel of a rotatable chuck I2. This chucklZ is driven by a motor l3 mounted on the .bed and connected with the chuck barrel by suitablereduction gearing indicated at I4. There may be further reduction gearing (not shown) within the motor casing l5 connecting the armature shaft with the pinion shown in dotted lines in the housing ll.

Mounted on the bed I0, is a shiftable carriage 20 shown as having a rack 2| connected with a pinion 23 on a cross shaft terminating in an operating handle 25.

As shown in Figs. 2- and 3, the chasers 39 are radially mounted in suitable ways in a ring-like head 40, having'ears 4! which lie between spaced lugs ZI'on the carriage. Suitable pins 43 may lock the parts together when .desired for use as shown in Fig. 2, but allow a ready removal of the head whenever desired to substitute a head carrying different size chasers for cutting a different size of pipe.

To position the chasers and holdthem efiectively either in their active or their withdrawn position, I provide a cam plateiil which is r0.- tatably mounted on the head by means of the overhanging confining ring 45 secured to the head. This cam plate is provided on its inner side with scroll grooves 5i which are, adaptedto receive pins 3| on the chasers 30.

Formed on the upper portion of the chaser head is a boss 48, in which is journalled a subshait 60 projecting from a lever arm Bl which adjacent the shaft is preferably formed into a disc-like portion 162 at the front of the boss. A suitable screw 63 with an overhanging head screws into the rear end of the shaft 60, whereby the shaft is retained in the boss. The lever arm H is shown as terminating in a ring-likefinger portion 65. The lever with its disc-like hub-portion and the shaft are preferably one integral ri e- The hub-portion 52 of the levermember is in effect a disc-crank, its pin indicated at being screwed into the upper portion of the hub membar. -There isanother pin 55 screwed intoan car 56 in the cam-plate 50, and these two pins are connected by a compound link-10, so that movement of the lever operates to shift the cam. The compound link 10 is composed of two members, namely a screw H .with a head "having a transverse hole embracingthe pin 65, and an internally threaded .sleeve 13 terminating in a head 14 with atransverse hole embracing the pin/55. These pins are in effect cap-screwshaving heads overhanging the faces of the link heads. The screw H snugly engages the thread in the sleeve 13.

It will be seen that the mechanism provides a link pivotally connected to the cam and the operating lever, and normally acting as one integral piece. When this lever is in the normal or down position as shown in full lines 2, the cam is in the position to hold'the chasers in their active position. To freethe .chasersfroni the pipe, it is only necessary to pull the lever over into the nearly upright position shown in dotted lines in Fig. 2. This turns the cam sufficiently to withdraw the chasers from the pipe indicated at A, so that the latter may be withdrawn freely from the cutting head.

I have above described the normal operation of the device, there being merely two positions. namely; the active position of the chasers where they may cut the thread, and the withdrawn position where they may free the pipe. The Withdrawn position, however, is not suflici'ent to bring the open ends 58 of the cam grooves into registration with the pins 3! of the chasers so that the chasers could be withdrawn from the machine. When the machine is being assembled, the chasers are put in place, their pins passing through the open ends 58 of the cam groove and then when the compound link is put in place with proper relative adjustment of its two parts for the standard, and is secured by the capscrews 65 and 55, the chasers are efiectively retained 1n the machine.

To remove a Worn or broken chaser, the operator removes the cap screw 55 connecting the compound link with the cam plate, then shifts the cam plate manually until the open ends of the grooves register with the chaser pins. This allows the removal of the chasers.

The disconnection of the cap screw 55 also enables adjustment to be made in the length of the compound link, to change the setting of the chasers a slight distance either way from the standard as desired. That is to say, when 'a slightly smaller diameter than the standard.

In normal operation, however, the two lines 89 and BI will be in exact registration.

It will be noted from Fig. 2 that I have made the head of the screw 65 of a form not adapted for an ordinary wrench, in contradistinction to the head of the larger cap-screw 55. Accordingly, it will be the screw which is removed by an ordinary wrench operation. This screw is larger so that there will be less chance. of wear and.

looseness resulting from its removal and replace- .ment.

If desired, I may provide a suitable frictional detent device to prevent inadvertent movement of the operating lever 64 from either its active or inactive position. This device, may conveniently be a ball 93 backed by a spring 9| as indicated in Fig. 3. Here a recess is made in the leverhub 62, and this recess is occupied by the compression spring and ball which latter is adapted in one position of the handle to occupy one delever 'to which it is pivoted, one 'end of said operating mechanism being pivoted to the head and the other end to the cam plate, the pivot pins of said link being transverse to the axial length of the link whereby the link is nonadjustable as to length while both its ends are thus attached, but adjustable as to length when one end is disconnected.

2. In a machine of the character described, thecomb'ination of a ring-like head, a set of chasers slidably mounted therein, a cam plate mounted on the head having scroll connections with the chasers whereby they may be shifted in and out as the cam plate is given a partial rotation, a lever pivotally mounted on the head, a compound link adapted to connect the lever with the cam plate, said link comprising an internally-threaded sleeve with a head and an externally threaded screw with a head, the screw occupying the sleeve, each of said heads having an opening through it transversely of the length of the head, and pins occupying the respective openings and connected respectively to an eccentric region of the lever and to the cam plate and prohibiting relative rotation of the screw and sleeve, whereby change in the length of the link is impossible until one of the pins is removed.

3. In a machine of the character described, the combination of a ring-like head, a set of chasers slidably mounted therein, a cam plate mounted on the head and having scroll connections with the chasers whereby they may be shifted in and out as the cam plate is given a partial rotationfa lever pivotally mounted on the head, a link comprising an internally threaded sleeve with ahead and an externally threaded screw with a head, the screw occupying the sleeve, each of said heads having an opening through it transverse of the axis of the threaded portion, and pins occupying said openings and threaded at their inner ends into the lever and cam respectively and prohibiting relative rotation of the screw and sleeve, whereby change in the length of the link is impossible until one of the pins is removed, said pins having heads at their outer ends overlapping the heads on the compound link, one of said pin-heads having an angular form suitable for wrench application.

4. In a machine of the character described, the combination of a frame, a set of chasers slidably mounted therein, a cam plate rotatively mounted on the frame and having scroll connections with the chasers whereby they may be shifted in and out as the cam plate is given a partial rotation, a lever pivotally mounted on the frame by means of a stud projecting from one side of the lever, a compound link comprising an internally threaded sleeve with a head rigid thereon and an externally threaded screw with a head rigid thereon, the screw occupying the sleeve, each of said heads having an opening through it transverse of the axis of its helical thread, one of said heads lying against that side of the lever which is opposite said stud and the other head lying against the cam plate, and headed screws having their shanks passing through said openings and screwing into the lever and cam plate respectively, and prohibiting relative rotation of the screw and sleeve, whereby change in the length 'of the link is impossible until one of the pins is removed.

ROBERT B. PEALER. 

